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A skyscraper is a tall, continuously habitable building. There is no official definition or height above which a building may clearly be classified as a skyscraper. Most cities define the term empirically; even a building of 80 meters (262 feet) may be considered a skyscraper if it protrudes above its built environment and changes the overall skyline.[citation needed]

Definition

The word "skyscraper" originally was a nautical term referring to a small triangular sail set above the skysail on a sailing ship. The term was first applied to buildings in the late 19th century as a result of public amazement at the tall buildings being built in Chicago and New York City. The first skyscraper was for many years thought to be the Home Insurance Building built in Chicago, Illinois in 1885. More recent evidence points to New York's Equitable Life Assurance Building built in 1870 preceding the Chicago building by 15 years and was the first office building built using a skeletal frame.[1]

The structural definition of the word skyscraper was refined later by architectural historians, based on engineering developments of the 1880s that had enabled construction of tall multi-storey buildings. This definition was based on the steel skeleton—-as opposed to constructions of load-bearing masonry, which passed their practical limit in 1891 with Chicago's Monadnock Building. Philadelphia's City Hall, completed in 1901, still holds claim as the world's tallest load-bearing masonry structure at 167 m (548 ft). The steel frame developed in stages of increasing self-sufficiency, with several buildings in Chicago and New York advancing the technology that allowed the steel frame to carry a building on its own. Today, however, many of the tallest skyscrapers are built almost entirely with reinforced concrete.[2]Pumps and storage tanks maintain water pressure at the top of skyscrapers.

A loose convention in the United States and Europe now draws the lower limit of a skyscraper at 150 meters (~500 ft).[3] A skyscraper taller than 300 meters (~1000 ft) may be referred to as supertall. Shorter buildings are still sometimes referred to as skyscrapers if they appear to dominate their surroundings.

The somewhat arbitrary term skyscraper should not be confused with the also ill-defined term high-rise. The Emporis Standards Committee defines a high-rise building as "a multi-story structure between 35-100 meters tall, or a building of unknown height from 12-39 floors"[4] and a skyscraper as "a multi-story building whose architectural height is at least 100 meters."[5] Some structural engineers define a highrise as any vertical construction for which wind is a more significant load factor than earthquake or weight. Note that this criterion fits not only high rises but some other tall structures, such as towers.

The word skyscraper often carries a connotation of pride and achievement. The skyscraper, in name and social function, is a modern expression of the age-old symbol of the world center or axis mundi: a pillar that connects earth to heaven and the four compass directions to one another.[6]

History

Before the 19th century

The Great Pyramid of Giza, circa 2560 BC, was 146 m tall and its height was unsurpassed until at least the 14th century AD.

The 16th-century city of Shibam consisted entirely of over 500 high-rise tower houses.

Modern skyscrapers are built with materials such as steel, glass, reinforced concrete and granite, and routinely utilize mechanical equipment such as water pumps and elevators. Until the 19th century, buildings of over six stories were rare, as having great numbers of stairs to climb was impractical for inhabitants, and water pressure was usually insufficient to supply running water above 50 m (164 ft).

The tallest building in ancient times was the Great Pyramid of Giza in ancient Egypt, which was 146 metres (479 ft) tall and was built in the 26th century BC. Its height was not surpassed for thousands of years, possibly until the 14th century AD with the construction of Lincoln Cathedral (though its height is disputed),[7] which in turn was not surpassed in height until the Washington Monument in 1884. However, being uninhabited buildings, none of these buildings actually complies with the definition of a skyscraper.

High-rise apartment buildings already flourished in classical antiquity: ancient Romaninsulae in Rome and other imperial cities reached up to 10 and more stories,[8] some with more than 200 stairs.[9] Several emperors, beginning with Augustus (r. 30 BC-14 AD), attempted to establish limits of 20–25 m for multi-storey buildings, but met with only limited success.[10][11] The lower floors were typically occupied by either shops or wealthy families, while the upper stories were rented out to the lower classes.[8] Surviving Oxyrhynchus Papyri indicate that seven-storey buildings even existed in provincial towns, such as in 3rd century AD Hermopolis in Roman Egypt.[12]

The skylines of many important medieval cities had large numbers of high-rise urban towers. Wealthy families built these towers for defensive purposes and as status symbols. The residential Towers of Bologna in the 12th century, for example, numbered between 80 to 100 at a time, the largest of which (known as the "Two Towers") rise to 97.2 metres (319 ft). In Florence, a law of 1251 decreed that all urban buildings should be reduced to a height of less than 26 m, the regulation immediately put into effect.[13] Even medium-sized towns at the time such as San Gimignano are known to have featured 72 towers up to 51 m height.[13]

The medieval Egyptian city of Fustat housed many high-rise residential buildings, which Al-Muqaddasi in the 10th century described as resembling minarets. Nasir Khusraw in the early 11th century described some of them rising up to 14 stories, with roof gardens on the top floor complete with ox-drawn water wheels for irrigating them.[14]Cairo in the 16th century had high-rise apartment buildings where the two lower floors were for commercial and storage purposes and the multiple stories above them were rented out to tenants.[15] An early example of a city consisting entirely of high-rise housing is the 16th-century city of Shibam in Yemen. Shibam was made up of over 500 tower houses,[16] each one rising 5 to 11 storeys high,[17] with each floor being an apartment occupied by a single family. The city was built in this way in order to protect it from Bedouin attacks.[16] Shibam still has the tallest mudbrick buildings in the world, with many of them over 100 feet (30 m) high.[18]

An early modern example of high-rise housing was in 17th-century Edinburgh, Scotland, where a defensive city wall defined the boundaries of the city. Due to the restricted land area available for development, the houses increased in height instead. Buildings of 11 stories were common, and there are records of buildings as high as 14 stories. Many of the stone-built structures can still be seen today in the old town of Edinburgh. The oldest iron framed building in the world, although only partially iron framed, is The Flaxmill (also locally known as the "Maltings"), in Shrewsbury, England. Built in 1797, it is seen as the "grandfather of skyscrapers”, since its fireproof combination of cast iron columns and cast iron beams developed into the modern steel frame that made modern skyscrapers possible. Unfortunately, it lies derelict and needs much investment to keep it standing.

An early development was Oriel Chambers in Liverpool. Designed by local architect Peter Ellis in 1864, the building was the world's first iron-framed, glass curtain-walled office building. It was only 5 floors high as the elevator had not been invented.[19][20][21] Further developments led to the world's first skyscraper, the ten-storey Home Insurance Building in Chicago, built in 1884–1885. While its height is not considered very impressive today, it was at that time. The architect, Major William Le Baron Jenney, created a load-bearing structural frame. In this building, a steel frame supported the entire weight of the walls, instead of load-bearing walls carrying the weight of the building. This development led to the "Chicago skeleton" form of construction.

Most early skyscrapers emerged in the land-strapped areas of Chicago, London, and New York toward the end of the 19th century. A land boom in Melbourne, Australia between 1888-1891 spurred the creation of a significant number of early skyscrapers, though none of these were steel reinforced and few remain today. Height limits and fire restrictions were later introduced. London builders soon found building heights limited due to a complaint from Queen Victoria, rules that continued to exist with few exceptions until the 1950s. Concerns about aesthetics and fire safety had likewise hampered the development of skyscrapers across continental Europe for the first half of the twentieth century (with the notable exceptions of the 26-storey Boerentoren in Antwerp, Belgium, built in 1932, and the 31-storey Torre Piacentini in Genoa, Italy, built in 1940). After an early competition between New York City and Chicago for the world's tallest building, New York took the lead by 1895 with the completion of the American Surety Building, leaving New York with the title of tallest building for many years. New York City developers competed among themselves, with successively taller buildings claiming the title of "world's tallest" in the 1920s and early 1930s, culminating with the completion of the Chrysler Building in 1930 and the Empire State Building in 1931, the world's tallest building for forty years. The first completed World Trade Center tower became the world's tallest building in 1972 for two years. That changed with the completion of the Sears Tower (later renamed the Willis Tower) in Chicago in 1974, which became the world's tallest building until 1998.

Modern skyscrapers

Taipei 101, formerly the world's tallest skyscraper, was the first to exceed the half-kilometer mark.

In the early 1960s structural engineer Fazlur Khan realized that the rigid steel frame structure that had "dominated tall building design and construction so long was not the only system fitting for tall buildings", marking "the beginning of a new era of skyscraper revolution in terms of multiple structural systems."[22] His central innovation in skyscraper design and construction was the idea of the "tube" structural system, including the "framed tube", "trussed tube", and "bundled tube".[23] These systems allowed far greater economic efficiency,[24] and also allowed efficient skyscrapers to take on various shapes, no longer needing to be box-shaped.[25] Over the next fifteen years, many towers were built by Khan and the "Second Chicago School",[26] including the massive 442-meter (1,451-foot) Willis Tower.[27] Chicago is currently undergoing an epic construction boom that will greatly add to the city's skyline. Since 2000, at least 40 buildings at a minimum of 50 stories high have been built or planned.[28] The Chicago Spire, Trump International Hotel and Tower, Waterview Tower, Mandarin Oriental Tower, 29-39 South LaSalle, Park Michigan, and Aqua are some of the more notable projects currently underway in the city that invented the skyscraper. Chicago, Hong Kong, and New York City, otherwise known as the "the big three," are recognized in architectural circles as having especially compelling skylines. A landmark skyscraper can inspire a boom of new high-rise projects in its city, as Taipei 101 has done in Taipei since its opening in 2004. Large cities currently experiencing skyscraper building booms include London in the United Kingdom, Shanghai in China, Dubai in the United Arab Emirates, and Miami, which now is third in the United States.[29]

History of tallest skyscrapers

At the beginning of the 20th century, New York City was a center for the Beaux-Arts architectural movement, attracting the talents of such great architects as Stanford White and Carrere and Hastings. As better construction and engineering technology became available as the century progressed, New York and Chicago became the focal point of the competition for the tallest building in the world. Each city's striking skyline has been composed of numerous and varied skyscrapers, many of which are icons of 20th century architecture:

The Flatiron Building, standing 285 ft (87 m) high, was one of the tallest buildings in the city upon its completion in 1902, made possible by its steel skeleton. It was one of the first buildings designed with a steel framework, and to achieve this height with other construction methods of that time would have been very difficult. Subsequent buildings such as the Singer Building, the Metropolitan Life Tower were higher still.

The Woolworth Building, a neo-Gothic "Cathedral of Commerce" overlooking City Hall, was designed by Cass Gilbert. At 792 feet (241 m), it became the world's tallest building upon its completion in 1913, an honor it retained until 1930, when it was overtaken by 40 Wall Street.

That same year, the Chrysler Building took the lead as the tallest building in the world, scraping the sky at 1,046 feet (319 m).[30] Designed by William Van Alen, an art deco masterpiece with an exterior crafted of brick,[31] the Chrysler Building continues to be a favorite of New Yorkers to this day.[32]

The Empire State Building, the first building to have more than 100 floors (it has 102), was completed the following year. It was designed by Shreve, Lamb and Harmon in the contemporary Art Deco style. The tower takes its name from the nickname of New York State. Upon its completion in 1931 at 1,250 feet (381 m), it took the top spot as tallest building, and towered above all other buildings until 1972. The antenna mast added in 1951 brought pinnacle height to 1,472 feet (449 m), lowered in 1984 to 1,454 feet (443 m).[33]

The World Trade Center officially reached full height in 1972, was completed in 1973, and consisted of two tall towers and several smaller buildings. For a short time, the first of the two towers was the world's tallest building. Upon completion, the towers stood for 28 years, until the September 11, 2001 attacks destroyed the structures. Various governmental entities, financial firms, and law firms called the towers home.

The Willis Tower (formerly Sears Tower) was completed in 1974, one year after the World Trade Center, and surpassed it as the world's tallest building. It was the first building to employ the "bundled tube" structural system, designed by Fazlur Khan.[25] The building was not surpassed in height until the Petronas Towers were constructed in 1998, but remained the tallest in some categories until Burj Khalifa surpassed it in all categories. It is currently the tallest building in the United States.

Momentum in setting records passed from the United States to other nations with the opening of the Petronas Twin Towers in Kuala Lumpur, Malaysia, in 1998. The record for world's tallest building remained in Asia with the opening of Taipei 101 in Taipei, Taiwan, in 2004. A number of architectural records, including those of the world's tallest building and tallest free-standing structure, moved to the Middle East with the opening of the Burj Khalifa in Dubai, UAE.

This geographical transition is accompanied by a change in approach to skyscraper design. For much of the twentieth century large buildings took the form of simple geometrical shapes. This reflected the "international style" or modernist philosophy shaped by Bauhaus architects early in the century. The last of these, the Willis Tower and World Trade Center towers in New York, erected in the 1970s, reflect the philosophy. Tastes shifted in the decade which followed, and new skyscrapers began to exhibit postmodernist influences. This approach to design avails itself of historical elements, often adapted and re-interpreted, in creating technologically modern structures. The Petronas Twin Towers recall Asian pagoda architecture and Islamic geometric principles. Taipei 101 likewise reflects the pagoda tradition as it incorporates ancient motifs such as the ruyi symbol. The Burj Khalifa draws inspiration from traditional Arabic art. Architects in recent years have sought to create structures that would not appear equally at home if set in any part of the world, but that reflect the culture thriving in the spot where they stand.

Today

Today, skyscrapers are an increasingly common sight where land is expensive, as in the centres of big cities, because they provide such a high ratio of rentable floor space per unit area of land. But they are built not just for economy of space. Like temples and palaces of the past, skyscrapers are considered symbols of a city's economic power. Not only do they define the skyline, they help to define the city's identity.

Supertall towers

At the time Taipei 101 broke the half-kilometer mark in height, it was already technically possible to build structures towering over a kilometer above the ground. Proposals for such structures have been put forward, including the Mile-High Tower to be built in Jeddah, Saudi Arabia[34][35] and Burj Mubarak Al Kabir in Kuwait. Kilometer-plus structures present architectural challenges that may eventually place them in a new architectural category.[36]

Future skyscrapers

The following skyscrapers are either approved or due to be completed in the near future:

Construction of the Pagcor Tower started in 2009, will be the second-tallest free-standing structure in the world when it is completed. Standing at a height of 665 meters, the tower will be located in Manila Bay near the Mall of Asia.

The Lotte Super Tower 123, a mixed-use skyscraper in Seoul, South Korea, will stand 555 meters (1,821 feet) in height upon its scheduled completion in 2014. The tower will house retail space, residences, and a luxury hotel.

Construction of the 133-floor, 640m supertallDigital Media City Landmark Building in Digital Media City, Seoul, South Korea, started in 2009, which will be the second-tallest building in the world when it is completed in 2015, housing the world's tallest observatory and hotels. Being constructed at the fastest speed among major skyscraper projects by South Korea's Samsung C&T (who also built Burj Khalifa), the supertall is the first skyscraper to contain an entire city inside a building, including the world's largest aquarium, a luxury department store, shopping malls, clinic center, high-tech offices, first-class apartments, six to eight-star hotels, a concert restaurant, a broadcasting studio and an art center.

Construction of the Shanghai Tower started on 29 November 2008.[37] The tower will be 632 m (2,073 ft) high and have 127 floors.[38][39] The building will feature a glass curtain wall and nine indoor gardens when it is completed in 2014.[40][41]

The Abraj Al-Bait Towers also known as the "Mecca Royal Clock Hotel Tower" is a complex under construction in Mecca, Saudi Arabia by the Saudi Binladin Group,the complex consists of seven towers the tallest tower (Hotel Tower) stand on a hight of 595 m (1,952 ft). Upon completion in 2011, the structure would have the largest floor area of any structure in the world with 1,500,000 square metres (16,137,600 sq ft) of floorspace.

Construction of the 123-floor, 555m supertall in Lotte World 2, Seoul, South Korea, started in 2005,however it is currently on-hold,it was expected to be completed in 2014.

Construction did start for a 610 m (2,001 ft) skyscraper in Chicago, however the estimated completion date is unknown, as the project is on hold.[42] The Chicago Spire, with 150 floors, would be the second tallest residential building in the world if completed. Designed by Santiago Calatrava, it would also hold the title of North America's tallest free-standing structure.[43]

The Port Tower is a building planned for Karachi, the financial capital of Pakistan, with the collaboration of local and foreign investors, in association with the Karachi Port Trust. When completed, the new structure will be 1,947 ft (593 m) high. The height of the tower has a special significance, representing the year Pakistan gained independence.

Construction of London's Shard of Glass started in March 2009, and is scheduled to be completed in May 2012, in time for the London Olympics.[46][47] At 310 m (1,017 ft), it is set to be the tallest building in the European Union.[48]

Sustainability

The skyscraper as a concept is a product of the industrialized age, made possible by cheap energy and raw materials. The amount of steel, concrete and glass needed to construct a skyscraper is vast, and these materials represent a great deal of embodied energy. Tall skyscrapers are very heavy, which means that they must be built on a sturdier foundation than would be required for shorter, lighter buildings. Building materials must also be lifted to the top of a skyscraper during construction, requiring more energy than would be necessary at lower heights. Furthermore, a skyscraper consumes a lot of electricity because potable and non-potable water must be pumped to the highest occupied floors, skyscrapers are usually designed to be mechanically ventilated, elevators are generally used instead of stairs, and natural lighting cannot be utilized in rooms far from the windows and the windowless spaces such as elevators, bathrooms and stairwells.

Despite these costs, the size of skyscrapers allows for high-density work and living spaces, reducing the amount of land given over to human development. Mass transit and commercial transport are economically and environmentally more efficient when serving high-density development than suburban or rural development. Also, the total energy expended towards waste disposal and climate control is relatively lower for a given number of people occupying a skyscraper than that same number of people occupying modern housing.[citation needed] Indeed, though the city of Paris, for example, has almost the population density of Manhattan, Paris' stringent building codes and unchanging borders have made it difficult to create the larger buildings and utilities needed for a growing population within the actual city limits.[citation needed] This inflexibility has led many important institutions and departments to locate outside of city limits (such as the La Défense business district and the Department of Transportation).

Quotations

"What is the chief characteristic of the tall office building? It is lofty. It must be tall. The force and power of altitude must be in it, the glory and pride of exaltation must be in it. It must be every inch a proud and soaring thing, rising in sheer exaltation that from bottom to top it is a unit without a single dissenting line."

—Louis Sullivan's The Tall Office Building Artistically Considered (1896)

References

^Ivars Peterson (April 5, 1986). "The first skyscraper - new theory that Home Insurance Building was not the first". CBS Interactive. http://findarticles.com/p/articles/mi_m1200/is_v129/ai_4501450/. Retrieved January 6, 2010. ""In my view, we can no longer argue that the Home Insurance Building was the first skyscraper," says Carl W. Condit, now retired from Northwestern University in Evanston, Ill., and author of several books on Chicago architecture. "The claim rests on an unacceptably narrow idea of what constitutes a high-rise commercial building," he says."If there is a building in which all these technical factors--structural system, elevator, utilities--converge at the requisite level of maturity," argues Condit, "it's the Equitable Life Assurance Building in New York." Completed in 1870, the building rose 7-1/2 stories, twice the height of its neighbors. To lighten the building and keep costs down, engineer George B. Post used a primitive type of skeletal frame in its construction. A great fire destroyed the building in 1912"

^Finniston, Monty; Williams, Trevor; Bissell, Christopher, eds (1992). "Skyscraper". Oxford Illustrated Encyclopedia of Invention and Technology. Oxford University Press. p. 322. ISBN 0-19-869138-6. "Modern skyscrapers such as the World Trade Center, New York, have steel and concrete hull-and-core structures. The central core–a reinforced concrete tower–contains lift shafts, staircases, and vertical ducts. From this core, the concrete and steel composite floors span on to a steel perimeter structure; a lightweight aluminium and glass curtain wall encloses the building. This type of construction is the most efficient so far designed against wind forces."